Catalyzes the ATP dependent decarboxylation of (R)-5- diphosphomevalonate to form isopentenyl diphosphate (IPP). Functions in the mevalonate (MVA) pathway leading to isopentenyl diphosphate (IPP), a key precursor for the biosynthesis of isoprenoids and sterol synthesis. {ECO:0000269|PubMed:18823933, ECO:0000269|PubMed:8626466, ECO:0000269|PubMed:9392419}. This is the function of ENSG00000167508 (MVD, mevalonate diphosphate decarboxylase).